Variety reports that DiCaprio first learned about the book from his father, George, and got to work with his Appian Way production company to lock in a film deal.

Legacy of Secrecy: The Long Shadow of the JFK Assassination researches the idea that Mob boss Carlos Marcello was the man who ordered the hit, having confessed as such to confidant Jack Van Laningham. Unfortunately for Marcello, Van Laningham was a deep-cover informant for the FBI. Waldron and Hartmann dug through declassified files and also found that many of Marcello’s close associates and family members were arrested in the wake of the assassination.

DiCaprio will most likely play Van Laningham in the final film, which Warner Bros., under its deal with DiCaprio’s team, is looking at getting out into cinemas for 2013, which also happens to be the 50th anniversary of the assassination itself.